Study On Mechanical Properties And Crack Propagation Law Of Yellow Sandstone Under Chemical

With the depletion of mineral resources in our country,to satisfy the needs of human beings and achieve sustainable economic development,it is necessary to explore those mines with complex geological environments.Water-bearing mines with complex hydraulic and acid-base environment are inherited with weak mechanical properties due to large water content and acid-base ions.This thesis obtain the mechanical properties and crack propagation laws of yellow sandstone under the action of different chemical solutions by doing relevant mechanical strength tests and monitoring the whole process of crack initiation,propagation and failure of the rock specimens.1)By monitoring the p H value and variation characteristics of yellow sandstones under hydrochloric acid solution,distilled water solution and sodium hydroxide solution,this thesis conducted uniaxial compressive tests and Brazil splitting tests of cylindrical specimens after 30,120,and 240 days corrosion.The failure characteristics and the trend of stress-strain curve under the action of three chemical solutions in different time intervals were obtained.2)This thesis conducted biaxial compression loading tests with confining pressure loadings of 5MPa,7.5MPa,10MPa on prefabricated parallel double-cracked slab samples under corrosion.By analyzing the stress-strain curves and the mechanical parameters variation,this thesis introduced the physical softening coefficient K′,the peak deterioration coefficientμ′and the elastic modulus deterioration rateυ_S to obtain the corrosion effect of slab samples under different solution and different corrosive times.3)The VIC-3D non-contact full-field strain system was used to monitor and analyze the entire process of initiation,propagation and failure of cracks on prefabricated parallel fissure slabs under different types of solution and surrounding pressures.Explore the fracture evolution mechanism of pre-cracked rock and the obtain influence of chemical solution corrosion composition and corrosion time on the crack propagation process.Figure 66;Table 3;Reference 65;...